1. Technical Field
The present invention relates to hinge devices in general, and particularly to a portable computer having a hinge device for coupling two chassis to each other to allow the two chassis to be opened and closed.
2. Description, of Related Art
In recent years, tablet personal computers (tablet PCs) with touch panel liquid crystal displays but no physical keyboard have become very popular. Tablet PC, which is easily portable and on which an input operation can be performed through a touch panel, can be easily operated.
However, a tablet PC does not include a physical keyboard, and thus, operations, such as an input of a long sentence, can be hindered. In view of this, a so-called convertible PC in which a display chassis provided with a display can rotationally moves to 360 degrees through 180 degrees with respect to a main body chassis provided with a keyboard is proposed. The convertible PC can be used in two ways, i.e., as a general laptop PC and a tablet PC, and thus, is very convenient for a user. A hinge device having a biaxial structure can be provided for the configuration described above.
The hinge device includes a pin capable of reciprocating between two shafts, and the pin is transferred between recessed portions formed in outer peripheral surfaces of the two shafts. In this manner, rotation of a shaft engaged with the pin is restricted, and rotation of the shaft not engaged with the pin is allowed so that it is selectively switched which one of the two shafts is rotated in accordance with an opening/closing angle position of the display chassis.
A chassis structure of portable information equipment has been rapidly downsized. Thus, a hinge device for coupling two chassis to each other also has needed to conform with the reduced thickness of equipment by reducing the distance between two shafts that are arranged in a thickness direction of the chassis.
In this respect, a pin is interposed between two shafts, and thus, the distance between the two shafts needs to be greater than or equal to an outer diameter of the pin. In addition, in this configuration, rotation of one of the shafts is stopped by engaging the pin with the recessed portion of each of the shafts, and thus, the outer diameter of the pin needs to be large to a certain degree. For this reason, it is difficult to further reduce the size of the configuration of the hinge device.
Consequently, it would be desirable to provide an improved hinge device that can selectively switch rotation of two shafts in accordance with an opening/closing angle position between two chassis.